docs: def is_reconciled(self):
          """Have transactions been imported and reconciled for this billing cycle?"""
          from hordak.models import StatementImport, StatementLine
          since = datetime(
              self.date_range.lower.year,
              self.date_range.lower.month,
              self.date_range.lower.day,
              tzinfo=UTC
          )
          if not StatementImport.objects.filter(timestamp__gte=since).exists():
              # No import done since the end of the above billing cycle, and reconciliation
              # requires an import. Therefore reconciliation can not have been done
              return False
  
          if StatementLine.objects.filter(
              transaction__isnull=True,
              date__gte=self.date_range.lower,
              date__lt=self.date_range.upper
          ).exists():
              # There are statement lines for this period which have not been reconciled
              return False
  
          return True